Dystonia is a syndrome of sustained muscle spasms of presumed central nervous system origin. Recent advances in molecular biology have permitted clearer understanding of the genetics of various forms of dystonia and suggest pathophysiological deficits at the origin of the clinical signs. Treatment has involved centrally-acting drugs, specifically the anticholinergic medications, as well as peripherally acting agents that block neuromuscular transmission (botulinum toxin). Some forms of dystonia are particularly responsive to levodopa. A systematic approach to the diagnostic and treatment evaluation of dystonic patients permits optimal care for long-term management.